1. Field of the Invention
The present invention relates to techniques of forming a shaped body such as a film or a micro structure on a substrate by applying ultra fine particles of brittle material such as ceramics to the substrate.
2. Description of the Related Art
A method of forming a film or a micro structure on a substrate by using ultra fine particles of brittle material such as ceramics by mixing brittle ultra fine particles with carrier gas and blowing the gas toward a substrate via a fine nozzle has been proposed. In order to provide desired physical properties of the film or micro structure, it is essential that the ultra fine particles in the film or micro structure have a desired bonding strength.
In practice, however, whether ultra fine particles can be bonded and molded at high density and strength at room temperature without any thermal assistance depends on the physical properties of the ultra fine particles to be used, and the reason for this is still not clear. Therefore, in order to obtain sufficient physical properties (mechanical and electrical characteristics and the like) using a conventional molding (film forming) method, it is usually required to heat a substrate to a temperature of several hundreds of OC or higher and thereafter bake it at a high temperature near the sintering temperature of ceramics (brittle material). In general sintering techniques for ceramics, it is also essential to bake ceramic material at a high temperature (at least 900xc2x0 C. or higher) in order to bond ultra fine particles by utilizing thermal diffusion phenomenon such as by a solid state reaction and a solid-liquid state reaction.
Since such heat treatment is necessary, it is impossible to apply ceramics directly to a substrate having a low heat resistance such as a plastic substrate, and also it is necessary to prepare a sintering furnace which makes the manufacturing process complicated. Such heat treatment may change the size precision or physical properties of a film or micro structure from that of before sintering.
A method of forming a film or a micro structure without any heat treatment, in which the film or micro structure has high density and strength and is made of brittle ultra fine particles bonded at a desired bonding strength, has long been desired.
It is an object of the invention to provide a method of forming a film or a micro structure without any heat treatment, which film or micro structure has high density and strength and other desired characteristics and which is made of brittle ultra fine particles bonded at a desired bonding strength.
In order to achieve the above-mentioned object, the invention provides a method of forming a brittle ultra fine particle shaped body at a low temperature, wherein a mechanical impact force is applied to brittle ultra fine particles supplied to a substrate to break the particles and bond them together.